[linux.git] / fs / binfmt_script.c

/*
 *  linux/fs/binfmt_script.c
 *
 *  Copyright (C) 1996  Martin von Löwis
 *  original #!-checking implemented by tytso.
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/binfmts.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/err.h>
#include <linux/fs.h>

static int load_script(struct linux_binprm *bprm)
{
	const char *i_arg, *i_name;
	char *cp;
	struct file *file;
	char interp[BINPRM_BUF_SIZE];
	int retval;

	if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
		return -ENOEXEC;

	/*
	 * If the script filename will be inaccessible after exec, typically
	 * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
	 * up now (on the assumption that the interpreter will want to load
	 * this file).
	 */
	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
		return -ENOENT;

	/*
	 * This section does the #! interpretation.
	 * Sorta complicated, but hopefully it will work.  -TYT
	 */

	allow_write_access(bprm->file);
	fput(bprm->file);
	bprm->file = NULL;

	bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
	if ((cp = strchr(bprm->buf, '\n')) == NULL)
		cp = bprm->buf+BINPRM_BUF_SIZE-1;
	*cp = '\0';
	while (cp > bprm->buf) {
		cp--;
		if ((*cp == ' ') || (*cp == '\t'))
			*cp = '\0';
		else
			break;
	}
	for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
	if (*cp == '\0') 
		return -ENOEXEC; /* No interpreter name found */
	i_name = cp;
	i_arg = NULL;
	for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
		/* nothing */ ;
	while ((*cp == ' ') || (*cp == '\t'))
		*cp++ = '\0';
	if (*cp)
		i_arg = cp;
	strcpy (interp, i_name);
	/*
	 * OK, we've parsed out the interpreter name and
	 * (optional) argument.
	 * Splice in (1) the interpreter's name for argv[0]
	 *           (2) (optional) argument to interpreter
	 *           (3) filename of shell script (replace argv[0])
	 *
	 * This is done in reverse order, because of how the
	 * user environment and arguments are stored.
	 */
	retval = remove_arg_zero(bprm);
	if (retval)
		return retval;
	retval = copy_strings_kernel(1, &bprm->interp, bprm);
	if (retval < 0) return retval; 
	bprm->argc++;
	if (i_arg) {
		retval = copy_strings_kernel(1, &i_arg, bprm);
		if (retval < 0) return retval; 
		bprm->argc++;
	}
	retval = copy_strings_kernel(1, &i_name, bprm);
	if (retval) return retval; 
	bprm->argc++;
	retval = bprm_change_interp(interp, bprm);
	if (retval < 0)
		return retval;

	/*
	 * OK, now restart the process with the interpreter's dentry.
	 */
	file = open_exec(interp);
	if (IS_ERR(file))
		return PTR_ERR(file);

	bprm->file = file;
	retval = prepare_binprm(bprm);
	if (retval < 0)
		return retval;
	return search_binary_handler(bprm);
}

static struct linux_binfmt script_format = {
	.module		= THIS_MODULE,
	.load_binary	= load_script,
};

static int __init init_script_binfmt(void)
{
	register_binfmt(&script_format);
	return 0;
}

static void __exit exit_script_binfmt(void)
{
	unregister_binfmt(&script_format);
}

core_initcall(init_script_binfmt);
module_exit(exit_script_binfmt);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/binfmt_script.c
	3	*
96de0e25	4	* Copyright (C) 1996 Martin von Löwis
1da177e4 LT	5	* original #!-checking implemented by tytso.
	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/string.h>
	10	#include <linux/stat.h>
1da177e4 LT	11	#include <linux/binfmts.h>
	12	#include <linux/init.h>
	13	#include <linux/file.h>
1da177e4 LT	14	#include <linux/err.h>
	15	#include <linux/fs.h>
	16
71613c3b	17	static int load_script(struct linux_binprm *bprm)
1da177e4	18	{
d7627467 DH	19	const char i_arg, i_name;
d7627467 DH	20	char *cp;
1da177e4 LT	21	struct file *file;
	22	char interp[BINPRM_BUF_SIZE];
	23	int retval;
	24
d7402698	25	if ((bprm->buf[0] != '#') \|\| (bprm->buf[1] != '!'))
1da177e4	26	return -ENOEXEC;
51f39a1f DD	27
	28	/*
	29	* If the script filename will be inaccessible after exec, typically
	30	* because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
	31	* up now (on the assumption that the interpreter will want to load
	32	* this file).
	33	*/
	34	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
	35	return -ENOENT;
	36
1da177e4 LT	37	/*
	38	* This section does the #! interpretation.
	39	* Sorta complicated, but hopefully it will work. -TYT
	40	*/
	41
1da177e4 LT	42	allow_write_access(bprm->file);
	43	fput(bprm->file);
	44	bprm->file = NULL;
	45
	46	bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
	47	if ((cp = strchr(bprm->buf, '\n')) == NULL)
	48	cp = bprm->buf+BINPRM_BUF_SIZE-1;
	49	*cp = '\0';
	50	while (cp > bprm->buf) {
	51	cp--;
	52	if ((cp == ' ') \|\| (cp == '\t'))
	53	*cp = '\0';
	54	else
	55	break;
	56	}
	57	for (cp = bprm->buf+2; (cp == ' ') \|\| (cp == '\t'); cp++);
	58	if (*cp == '\0')
	59	return -ENOEXEC; /* No interpreter name found */
	60	i_name = cp;
	61	i_arg = NULL;
	62	for ( ; cp && (cp != ' ') && (*cp != '\t'); cp++)
	63	/* nothing */ ;
	64	while ((cp == ' ') \|\| (cp == '\t'))
	65	*cp++ = '\0';
	66	if (*cp)
	67	i_arg = cp;
	68	strcpy (interp, i_name);
	69	/*
	70	* OK, we've parsed out the interpreter name and
	71	* (optional) argument.
	72	* Splice in (1) the interpreter's name for argv[0]
	73	* (2) (optional) argument to interpreter
	74	* (3) filename of shell script (replace argv[0])
	75	*
	76	* This is done in reverse order, because of how the
	77	* user environment and arguments are stored.
	78	*/
b6a2fea3 OW	79	retval = remove_arg_zero(bprm);
	80	if (retval)
	81	return retval;
1da177e4 LT	82	retval = copy_strings_kernel(1, &bprm->interp, bprm);
	83	if (retval < 0) return retval;
	84	bprm->argc++;
	85	if (i_arg) {
	86	retval = copy_strings_kernel(1, &i_arg, bprm);
	87	if (retval < 0) return retval;
	88	bprm->argc++;
	89	}
	90	retval = copy_strings_kernel(1, &i_name, bprm);
	91	if (retval) return retval;
	92	bprm->argc++;
b66c5984 KC	93	retval = bprm_change_interp(interp, bprm);
	94	if (retval < 0)
	95	return retval;
1da177e4 LT	96
	97	/*
	98	* OK, now restart the process with the interpreter's dentry.
	99	*/
	100	file = open_exec(interp);
	101	if (IS_ERR(file))
	102	return PTR_ERR(file);
	103
	104	bprm->file = file;
	105	retval = prepare_binprm(bprm);
	106	if (retval < 0)
	107	return retval;
3c456bfc	108	return search_binary_handler(bprm);
1da177e4 LT	109	}
	110
	111	static struct linux_binfmt script_format = {
	112	.module = THIS_MODULE,
	113	.load_binary = load_script,
	114	};
	115
	116	static int __init init_script_binfmt(void)
	117	{
8fc3dc5a AV	118	register_binfmt(&script_format);
8fc3dc5a AV	119	return 0;
1da177e4 LT	120	}
	121
	122	static void __exit exit_script_binfmt(void)
	123	{
	124	unregister_binfmt(&script_format);
	125	}
	126
	127	core_initcall(init_script_binfmt);
	128	module_exit(exit_script_binfmt);
	129	MODULE_LICENSE("GPL");